The present invention relates generally to light energy irradiators, and more particularly to an irradiator having novel structural components that provide improved cooling of light energy reflector surfaces without diminishing the efficiency of the light energy source and which enable relatively inexpensive manufacture of custom sizes for various applications.
Light energy irradiators for obtaining relatively intense energy radiation are well known and find many applications in research, manufacturing and the medical field. For example, researchers, test engineers and production engineers use ultraviolet ("UV") irradiators in such diverse applications as curing of photopolymer paints, inks and coatings; photoactivation of UV sensitive adhesives; photoresist activation; and graphic arts exposure, etc. Light energy irradiators find application in the dental field for curing polymers and the like. Typically, the known irradiators utilize a light energy source, such as a fluorescent or mercury vapor lamp, or a cal rod, designed to produce light energy radiation in the 185-1200 nanometer range. The light energy source is conventionally supported adjacent a reflector surface operative to provide either a focused or nonfocused optical configuration. For example, when used for curing, a reflector system having an elliptical profile reflector surface provides a focused optical configuration wherein the light energy is concentrated into a narrow beam on the curing surface. Elliptical reflector systems find particular application in curing fast moving films such as printing inks carried on a conveyor.
A reflector system having a semi-circular or parabolic profile reflector surface provides a nonfocused optical configuration wherein the light energy acts over a relatively wide area. This optical configuration permits one or more irradiators to be positioned either across or parallel to the direction of movement of a curing surface for greater exposure time, and finds particular application in curing thicker, slow-moving films such as sensitive adhesives.
In utilizing irradiators having either focused or nonfocused optical configurations, many applications require a custom size irradiator. Irradiators are known that employ extruded aluminum housings having parabolic or elliptical reflector surfaces formed integrally on the housing, such as a polished reflector surface, or having concave parabolic or elliptical support surfaces formed on the housing and on which are mounted reflector sheets, such as polished aluminum, to provide the desired optical reflector configuration. A significant problem with prior irradiators having optically polished reflector surfaces formed either integrally on an extruded aluminum housing or defined by mounted reflector sheets is that the reflector surfaces deteriorate over time and are difficult and expensive to replace. Prior irradiators have also employed quartz housings having integral concave elliptical or parabolic light energy reflector surfaces formed thereon. A coating may be put on either the quartz or aluminum reflector surfaces so that only selected wavelengths are reflected, with the non-reflected wavelengths being absorbed by the quartz or aluminum housing. This can result in similar heat problems as the quartz and aluminum housings become heated by the non-reflected wavelengths.
In manufacturing prior light energy irradiators, it has been a conventional practice to make a number of different size housings for use in standard size irradiators. If a custom size is required, that is, a size other than a standard production size, the various components must be specially made. This is a time consuming process and relatively expensive. Thus, a light energy irradiator that can be readily custom made to different length sizes and reflector surface configurations at relatively low cost and which overcomes the heat problems experienced with prior irradiators would provide substantial economic and operational advantages over the prior known light energy irradiators.